Truss booms for material handling are well known. For example, Christenson, et al., U.S. Pat. No. 4,159,059, June 26, 1979, discloses a truss boom for a material handling truck, in which a truss boom attachment for mounting to a fork assembly on a material handling truck is disclosed. Drott, et al., U.S. Pat. No. 4,251,181, Feb. 17, 1981, discloses a coupling apparatus for truss booms, and the like.
Truss booms are used in construction, usually in the construction of one, two, and sometimes three story buildings. They are useful, primarily, in the placement of truss assemblies in position along the length of the building at the roof or between floors. Trusses are large and require very specific placement. It is common to use a hydraulically driven arm to place loads at higher levels. However, in handling trusses, special problems are encountered in that the truss is particularly cumbersome and difficult to handle and must be lifted to higher levels than ordinarily experienced in material handling.
Truss booms, such as described by Christenson, et al., have been designed and have been in use for some time. A problem common among truss booms, however, is that their load carrying capacity is very limited and they are not adjustable insofar as the length of the boom is concerned. Sometimes, it is not possible to maneuver the truck into a satisfactory position for using a conventional boom, such as is disclosed by Christenson, et al., for example.
The present invention overcomes the deficiencies of the prior art by a unique truss boom design in which the truss boom is extensible and the truss boom includes a compression member and two extension members, the load being carried directly along the compression member, rather than offset, as is conventional.